A cheap device you can buy on Amazon or Craigslist may be what's causing a huge uptick in car burglaries

YouTube/Simple MisfitsWhile key-free car doors are meant to make it more convenient to get into your vehicle, tech-savvy thieves may have discovered a new way to use this capability to their advantage.

Burglars may be using a device called a "power amplifier" to break into cars with keyless doors without leaving a trace of their entry, according to The New York Times.

Here's how a power amplifier works, as explained by The Times:

In a normal scenario, when you walk up to a car with a keyless entry and try the door handle, the car wirelessly calls out for your key so you don't have to press any buttons to get inside. If the key calls back, the door unlocks. But the keyless system is capable of searching for a key only within a couple of feet.

The device amplifies the car's ability to search for the nearby key, thus making it possible for a key that's hundreds of feet away (say, in a nearby house) to be detected and unlock the door.

A quick Google search shows that these power amplifiers are primarily used by technicians hoping to boost wireless signal strength. The more expensive models go for well over $100, but you can find models as cheap as $17 on sites like Amazon and Craigslist, writes The Times.

Many regions around the US are reporting an uptick in stolen cars, which, when recovered, show no signs of forced entry. Authorities in Long Beach, California, for example, have been looking into this phenomenon specifically. The Long Beach Police obtained video of the thieves in action and saw them "holding a device," reports ABC News.

While this device seems to be helping the burglars perform their heists, the police are still unclear on exactly what it is. These power amplifiers may indeed be the culprit. Experts told The Times that the best way to avoid this problem is by putting the key dongle into the freezer.